Introduction to Fanyin Cave: Fanyin Cave has always been an important landscape in Mount Putuo. Fanyin Cave and Chaoyin Cave face each other in the north and south. The Chaoyin Cave and the Chaoyin Cave have their own characteristics and are collectively called the "Two Cave Chaoyin Cave". The Green Drum Base is inserted into Putuo Yang, where the roaring waves crash against the cliffs and the sound of the tide shakes the cave. It roars day and night, just like a drum, so it is also called "Jinggu Lei".